fix exception when file does not exist

fixes https://git.clan.lol/clan/clan-core/issues/488

pkgs/clan-cli/clan_cli/webui/routers/root.py

@@ -30,6 +30,8 @@ async def root(path_name: str) -> Response:
             if not filename.is_file():
                 log.error("File not found: %s", filename)
                 return Response(status_code=404)
+        else:
+            return Response(status_code=404)
 
     content_type, _ = guess_type(filename)
     return Response(filename.read_bytes(), media_type=content_type)

pkgs/clan-cli/tests/test_static_files.py

@@ -0,0 +1,10 @@
+import pytest
+from api import TestClient
+
+
+@pytest.mark.impure
+def test_static_files(api: TestClient) -> None:
+    response = api.get("/")
+    assert response.headers["content-type"] == "text/html; charset=utf-8"
+    response = api.get("/does-no-exists.txt")
+    assert response.status_code == 404